Question

Why 82.5°E has been selected as the standard meridian of India

Answer 1

Due to  this great  longitudinal extent the sun rises or sets almost two hours earlier in the eesternmost part than in the westernmost part.To avoid any confusion with respect to time at different places in India ,the almost centrally located longitude of 82 1/2°E has been selected as the standard meridian for the whole country.The local time of the standard meridian is used as the standard time for India and is called the Indian Standard Time.